Despite USFDA nod, expert opinion on plasma therapy remains divided

A day after the US Food and Drugs Administration (USFDA) decided to give Emergency Use Authorisation (EUA) to convalescent plasma therapy, the opinion among Indian doctors on its utility is mixed. While some say it works in the ‘right’ patients, another section is calling for further trials.

The approval given by the USFDA was based on the Mayo Clinic protocol. The US has an initiative called the Expanded Access Program (EAP) for Covid-19. Mayo Clinic started testing plasma therapy under the EAP and others joined in subsequently, said SK Sarin, Director of the Institute of Liver and Biliary Sciences (ILBS).

Last month, the ILBS became India’s first institution to create a plasma bank for treating Covid-19.

Randomised controlled trial

In convalescent plasma therapy, plasma collected from patients recovered from Covid-19 is injected into certain types of critical patients. However, an interim analysis of a randomised controlled trial (RCT) carried out at the All India Institute of Medical Sciences, New Delhi, did not find this therapy — classified as investigational therapy by the Indian Council of Medical Research (ICMR) — could reduce mortality, said a doctor at the Thiruvananthapuram Medical College who did not want to be named. According to him, multiple centres in India are participating in the RCT, whose results are not out yet.

Sarin said there was no EAP kind of programme in India. “Everyone who wanted to do clinical trials (on plasma therapy) had to take individual permission. This limited the scope of clinical trials in India. On the other hand, the US had a programme and a protocol that could be accessed by anybody. If we had a similar programme, we would have had a larger data set,” he said. As per the USFDA statement, the plasma therapy was tried out in around 70,000 patients there.

“In my opinion, plasma therapy may work in correctly chosen patients. Whether it will reduce mortality or not, we still don’t know. But morbidity is seen to decrease,” said Sarin, whose institution has supplied plasma for 700 patients so far. According to him, the ILBS plasma bank still has 900 units of plasma, which will be available to Covid-19 hospitals in and around Delhi.

What is special about plasma supplied by ILBS is that it has a higher concentration of neutralising antibodies against the SARS-Cov2 virus. As currently there is no drug available against the virus, the plasma with high neutralising antibody content is likely to be more effective, as these antibodies can go and bind to the virus, he argued.

Kerala’s protocol

Meanwhile, the Kerala doctor said so far 50 patients have received plasma therapy in the State. The therapy is given on compassionate grounds. “I cannot say whether it had positive impact on patients as they also received other treatments. Moreover, doctors who use a particular therapy over a period of time tend to be positive about its outcomes. That is why RCT is critically important,” he said.

Significantly, Kerala has made some changes in plasma therapy protocol. As per the protocol issued on August 15, it can also be used in moderate to severe patients, vis-à-vis only severe patients earlier.

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